Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Interest Rate Derivative Assets, at Fair Value	$ 3,254	$ 5,735
Accounts and Notes Receivable, Net	10,000	0
Principal components of other assets
Deferred federal income tax asset	497	1,902
Lease incentives and premiums, net of amortization of $41,246 and $39,638, respectively	74,515	96,587
Flight equipment held for sale	707	3,834
Other assets	28,533	27,417
Total other assets	141,210	148,398
Amortization of lease incentives and lease premiums	41,246	39,638
Deposits on Flight Equipment	$ 23,704	$ 12,923